Bacterial populations of mosquito breeding habitats in relation to maize pollen in Asendabo, south western Ethiopia

Mosquito larvae feed on particulate organic matter including microorganisms. This study was conducted to investigate the diversity and abundant bacteria of Anopheles mosquito larva breeding habitats and to evaluate the contribution of maize pollen as source of nutrients for bacterial growth. The nutrient composition (COD, NH3-N and TP) of the larva breeding habitats water samples were measured by HACH 2010. Bacteria were isolated and enumerated from 18 water samples of larva habitats. The abundance of bacteria in the larva breeding habitats was significantly different. Bacteria were found to be grown abundant in habitats close to maize pollen sources (tasseled zone). This implies that maize pollen contributes to bacterial abundance. The Pearson Correlation showed that there was positive relationship between bacterial abundance and physicochemical characteristics of the water samples. The bacterial population in the habitat was dominated by species of Bacillus, Pseudomonas, Micrococcus and Serratia. The dominant bacteria were tested for their capability to grow on maize pollen medium. The growth kinetics of bacteria on maize pollen broth was performed to 18 h culture using JENWAY spectrophotometer at 600 nm wave length. The bacteria could show optimum growth on Maize Pollen broth at 15 g/l as of nutrient broth. The release of maize pollen during anthesis in rainy season in habitats close to larva breeding pool and its nutriment quality support proliferation of large array of bacteria which results in increased larval nourishment. Increased malaria transmission in Asendabo could thus be caused as the bacteria serve as source of nutrients for mosquito larva.